| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the withstand voltage between a power conversion device and the case thereof for the reduction in the size thereof even if the main circuit voltage of the power conversion device is high. <P>SOLUTION: The power conversion device is composed of rectifiers 11 and 12, an inverter 15, smoothing capacitors 13 and 14 connected with a direct- current main circuit which connects together the direct-current sides thereof, and respective control circuits which control them. The power conversion device is placed in the case 10 made of conductive material, and the case 10 is insulated from ground. A direct-current middle potential (M potential) point is determined, where the potential from the positive pole P of the direct-current main circuit of the power conversion device placed in the case 10 and the potential from the negative pole N thereof are equal to each other. The direct-current middle potential point and the case 10 are connected with each other, and the reference potential of the control circuits is fixed at the middle direct-current potential. Thus, the values of withstand voltage can be reduced between the power conversion device and the case 10 and between individual pieces of equipment. <P>COPYRIGHT: (C)2004,JPO |
